Improvement in cut-off-valve gear



- UNITED STATES e PATENT iIrK-'IE- i. t.

K. H. LOOMIS, OF BALTIMORE, MARYLAND.

IMPROVEMENT |N`- CUT-oFF-VALVE cil-:Aa`

Specification forming part of Letters Patent No. 49,284, dated August 8,1865.

i cut-off valves for which Letters Patent were granted to me on the 23d day of August, 1864; and my invention consists of devices, fully described hereinafter, by which the construction and operation of the mechanism for cutting oft the steam previous to its admission into the valve-chest of an engine may be greatly simplitied. Y

In order to enable others skilled in the art to make and use my invention, I will now proceed to describe its construction and operation.

On reference to the accompanying drawings, which form part of this specification, Figure 1 is a longitudinal sectional elevation of a cutoff valve with my improvements; Fig. 2, an end view looking in thedirection of the arrow, Fig. 1, and Fig. 3 a section on the line 12, Fig. 1.

Similar letters rel'er to similar parts throughout the severalviews.

A is the valve-chest, within which is a. chamber, X, the latter being contracted at the center, where there is a seat for the tapering valve B, which is secured to the valve-spindle c. Through the head I) ot' the chest passes a set-screw, E, the conical point of which projects into a corresponding recess in the end of thevalve-spindle, the opposite head,D', having an opening for the passage ot' the valve-spindle, and being provided with the usual packing-box,E.

From the head D project two rods, o o, on the outer ends of which is a yoke, I, the latter being adjusted to or from the head by nuts p p on they ends ot' the rods, and against this yoke bears a collar, J, on the end ot' the spindle C.

In the inlet branch a of the chest is an opening, c,whicl1 communicates through narrow longitudinal openings c e e i iz' with the chamber X, and in the exit branch Z, which is bolted to the steam-chest of an engine, is an opening, c',

which communicates with the said valve-chest,

and also with the chamber X through openings i and i".

In the valve B are openings e e "and 'i'. 'i' l i', which correspond in shape and size to the openings e and t' in the valve-chest.

' To the outer end of thevalve-spindle C is secured a lever, F, in the upper end of which is a curved slot, m, and in the lower end a straight j .l j slot, a, and in the slots slide pins projecting. j

from a plate, G', to the center of which is jointed loosely the lower end of the governorrod Y, so that when the speed. atwhich the il governor revolves is diminished the `plate `Gr` will be raised toward the upper` end of the lever F.

To the upper end of the platefG-is jointed e e one end of a rod, H, on which are twoadjusti able blocks, k 7c, and at one side ot this rod vibrates a lever, W, which is operated from any l suitable moving portion of the engine, a pin at the side of the lever being brought alternately against each of the blocks k k, `so as to t i impart an intermittent reciprocating motion", e

to the rod.

1t willv be apparent thatas the rod Hslides j: back and forth the valve B will be caused to i 1 rotate first in one direction a'nd then in they;

other, the ports or openings in the valve being brought opposite to and carried beyond those j l in the steam-chest. When the speed of the engine is suddenly diminished, so that the action i ot' the governor raises the plate G toward the f upper end of the lever F, (the rod H coin# ciding with the line z, Fig. 2,) the valve B will revolve more slowly than when the plate and` rod are depressed to the position shown by the line y, Fig. 2. The openings in the valve therefore coincide for a greater length of time withf the openings in the chest, and a proportion# atel y greater amount of steam is admitted into., e. The reverse of this is the case e f the cylinder. when the speed of the engine is accelerated,

the plate and rod being then lowered so that l" the openings in the valve-are carried rapidly across the openings in the chest,the steam be-` ing therefore quickly cut oft' from the cylinder. i; i

It is important that the slot m should be t Y curved to vcorrespond with the arc of a circle of which the'centeris the pin to which the` opposite end of the lever H is hung, as otherwise an equal reciprocating motion imparted to the lever after the plate G had been moved from its rst position would turn rthe valve to a greater extent in one direction than in the other.

When the valve becomes Worn it will be apparent that it may be moved close to its seat by adjusting the yoke .l to a greater distance from the plate D and by bringing the setscreW E firmly up to the rear end ofthe valvespindle after adjustment, the collarJ preventing the valve from being wedged too tightly into its seat.

111 ordinary engines provided with cut-oft' valves the latter are operated by an additional eccentric7 as it is necessary that the steam should be admitted to the cylinder for only a short time after the usual valve has opened the port.

In my improvement I am enabled to dispense with the supplementary eccentric by the use of the lugs lc 7c, in combination with an arm which alternately shuts the same, lthis arm being-driven by any moving part of the ma- ,ebinery lt will be apparent that by imparting to the arm Wa uniform motion, and by adjusting the lugs 7c cto a greateror less distance apart the. arm will be brought in contact with the lugs and Will move the rod H of the valve at such time as :may be required in order to -admit or cut oft' the steam at any desired point of the stroke.

It will lbe evident Without further description that by the above-.described devices the dinary engines now in use.

Without conining myself to the exact con` struction and arrangement of the parts herein described,

I claim as my invention and desire tosecure by Letters Patentl. The .plate G, sliding in the lever F,.at tached to thevalve-spindle and jointed to and operated by the governor-rod Y, and slidingrod H, or its equivalent, all substaniiallyas and forthe purpose specified.

2. The rod H, with its adjustable lugs k lr, connected to the plate Gr, and operating bythe vibrating lever Wr or its equivalent, substantially as and for the purpose set forth.

In testimony Whereof,I have signedmy name to y'this specification in the presence of two subscribin g witn esses.

K. H. LOGMIS.

Witnesses CHARLES E. FOSTER, J oHN WHITE 

